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Confined Space Entry Rescue Hazards

Detecting hazards and protecting workers

From gas detection to breathing apparatus, Gary Watts looks at the essential equipment to keep workers, and rescuers, safe in confined spaces.

The HSE regulations define confined space works as: “Any place in which, by virtue of its enclosed nature, there arises a specified risk of harm from fire or explosion; loss of consciousness from increase in body temperature; loss of consciousness or asphyxiation from gas, vapour or lack of oxygen; drowning or asphyxiation from free slowing solids.”

The regulation also surmises that confined space entry should be avoided if an alternative means of achieving work can be completed. However, if entry is unavoidable, then a safe system of work should be followed.

Confined Space Rescue

No person should enter or carry out work in a confined space without sufficient arrangements for the rescue of persons in the event of an emergency. Also, where there is a likely consequence of a relevant risk, the provision of resuscitation equipment must be provided.

“rescuers account for 60% of confined space deaths”

Risk versus response

Guidance on defining what is or isn’t a confined space is in itself open to individual interpretation and in recent years I have witnessed contractors attempting to declassify what is clearly an enclosed works location, in an attempt to bypass the costs associated with confined space works. I have also seen method statements for confined space work created by someone office based who hasn’t even seen the location first hand, and therefore perhaps without a working understanding of the hazards associated. A real appreciation of the hazards that confined spaces pose to a workforce is imperative in order to safeguard them during operational requirements.

With confined space works covering a wide range of industries and operational requirements, there are various working scenarios to contend with and one plan does not fit all eventualities. Confined spaces are not just ‘holes in the ground’, and as industry and commerce evolve, so do the associated workplace locations and hazards. Appropriate consideration must be given to safe systems of work in each environment based on its own merits. Every employer has a legal duty of care to safeguard their employees or contractors during work. Equally, every employee or contractor has a duty of care to ensure that safe systems of work are adhered to. Through active input from both employer and employee, safe working processes should be achievable.

Emergency rescue planning


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A consideration to all aspects of confined space works from prior planning, appropriate workforce selection, suitable equipment and training, recognition of the task to achieve, as well as an emergency action plan, will ensure that – whatever the outcome – you have at the very least demonstrated due diligence. That said, accidents can and do still happen. Around 60% of all UK confined space related fatalities are not attributed to the individual who became impaired in the first place, but rather the ‘would be rescuer’ who went in to assist.

This figure confirms, to some extent at least, that considerations to emergency planning are perhaps not what they should be. This could be due to a lack of understanding or training, inadequate or non-existent safety rescue equipment, or missing/ inappropriate medical response equipment. Whatever the reason, somebody somewhere in the loop didn’t pay due diligence to the severity of the workplace hazards.

Risks associated with workplace hazards can be reduced with the appropriate management and enforcement of additional safety measures. What cannot be reduced, however, is the severity of those hazards if they are realised. It is perhaps this element of planning the safe working system that is overlooked the most. A general perception is that by addressing the risk, the severity associated with that risk is also somehow reduced.

If something can go wrong in the workplace, it should be anticipated and planned for with appropriate measures in place to meet it. In the event of an operative becoming impaired within a confined space for whatever reason, an appropriate and proportionate response should be in place. Appropriate consideration towards worst case scenarios during confined space works will enable the site operatives to better respond to potential emergency situations. The decisions made and actions taken during and immediately after an on-site emergency may result in lives being saved or lost.

Irrespirable environment

Gas detection is an essential element of working safely within confined spaces. While confined space training teaches us to use our five senses, these alone would not stand much chance of detecting most hazardous gasses. After all, when exposed to highly noxious gases such as hydrogen sulphide, our senses betray us. Rapidly deadening the sense of smell, a user is temporarily lulled into the false sense that the hazard has passed – only to then succumb to the gas shortly after.

Employers have a wide range of options when it comes to detecting harmful working environments, from fixed monitoring systems, interlinked and infrared units, to small personal issue monitors.

“it would be a foolhardy individual who chose to work without a gas monitor present”

Personal issue gas monitors are designed to be lightweight and portable, with both audible and visual indicators to warn operatives of potentially hazardous changes within confined space environments. Generally they should be worn high up on the chest, to detect gases within a worker’s breathing zone. Measuring the ambient air in parts per million, these units are built with buffers that can be varied according to the potential hazards in your environment, to alarm at the earliest warning of changes to gases in the air.

Standard multi-gas units are generally calibrated to monitor levels of oxygen, carbon monoxide, hydrogen sulphide and combustible gases. On alarm activation, the levels of harmful gas the operative is exposed to may not yet be at a life threatening level, but all entrants should still make an immediate safe exit. A review on the cause for alarm can be reviewed from the relative safety outside the confined space.

I say ‘relative’ safety, as there have been incidents in which workers have been overcome by gas before even entering a confined space – just opening the hatch was enough. Devastatingly the workers even had the correct PPE with them, but had not yet put in on as they did not perceive there to be a risk.

Invisible Hazards

With almost all gasses being invisible to the naked eye, this constant monitoring of the environment is required to warn of a change in gases present. The potential for oxygen displacement due to other gasses, or asphyxiation from a hazardous heavier gas, cannot be detected without the aid of such equipment. Given the number of confined space fatalities attributed to asphyxiation, it would be a foolhardy individual who chose to work without a gas monitor present.

Once an environment has been deemed irrespirable and/or harmful to operatives, the approach for entry must be revised to ensure safety to all entrants upon re-entry. Various options for safety could be considered such as the introduction of forced air, use of negative pressure filtered respirators or closed circuit positive pressure breathing apparatus. All of these offer some level of protection, but correctly selecting the right method is essential to sustain life in a hazardous or irrespirable environment.

Breathing apparatus selection

Escape breathing apparatus during confined space works is essential for all operatives, although it’s not often operatives actually experience using one ‘in anger’. As a means of escape, these reasonably small units offer the wearer some 10 or 15 minutes of air supply, and rarely cause an operative physical difficulty during an emergency exit from a confined space.

During confined space works where there is a realised or potential risk of an irrespirable environment, closed circuit breathing apparatus must be considered; not only to provide safety during work, but also to facilitate an emergency response. These self-contained units will enable the wearer to facilitate a task in a potentially gas filled/oxygen deficient environment. Additionally, suitable training for personnel to potentially enter this environment with positive pressure breathing apparatus is required. More than this though, some level of experience in actually achieving a task (including a potential rescue of another person) while wearing this potentially cumbersome apparatus should also be taken in to account.

"any planning for an emergency situation should take all these elements into account in order to facilitate a successful rescue"

To undertake any physical task while wearing a breathing apparatus working set is an entirely different experience than without said equipment. Even with lightweight carbon composite cylinders and back plates with a degree of flexion, the donning of BA means the wearer is mindful of a reduction in the level of physical free-flowing movement. Add an unexpected emergency incident into the equation and there will undoubtedly be an elevation of emotional stress and strain.

It’s said that statistically you are much more likely to have to offer some form of immediate first response during a medical or emergency incident to someone you know rather than someone you don’t. In a confined space related incident, this fact would only compound the pressure that a designated rescuer would experience. The effect could cause the already stressed rescuer to have an elevated pulse rate, which in turn would elevate the breathing rate. This physiological effect could potentially cause the wearer to breathe a breathing apparatus cylinder down quicker, resulting in a reduced working time before cylinder replacement is required.

The application of an airline fed closed circuit breathing system could offer an alternative and can offer a much longer working time for the user if required. Equipment such as an airline trolley (with a bank of multiple cylinders), or an air compressor (providing a safe source of external breathable air) may be considered during any long duration confined space works in potential or realised irrespirable environments.

Ultimately the confined space itself, along with works to be achieved, should direct the individual responsible for prior planning on appropriate selection of breathing apparatus where it’s required. Additionally, any planning for an emergency situation should take all these elements into account in order to facilitate a successful rescue. An awareness of the confined space schematics along with appropriate safety or rescue equipment should also be considered.


Entering any confined space in order to undertake a task invariably comes with some level of risk attached. An irrespirable environment is potentially one of the most hazardous risks an operative can be exposed to. Even with gas monitoring equipment, unidentified pockets of gasses can be released during movement inside the confined space, potentially rendering any and all those inside unconscious or worse.

Some level of emergency provision for entrants should be immediately accessible, such as escape breathing apparatus. Once an irrespirable environment has been identified (present or potential), the only decision to make from that point is what type of positive pressure contained breathing apparatus is best suited to facilitate the task. Appropriately trained individuals should taught to not only use this breathing apparatus, but also how to achieve rescue of another operative. This training should then be rehearsed whenever possible to enforce and underpin best practice in the event of an emergency confined space incident.

This may sound excessive and perhaps not a reasonable or proportionate operation to undertake. But unless you provide an emergency response in confined spaces regularly, the undertaking of this hazardous task will not come naturally. To equate this to layman’s terms, for those who drive, I can almost guarantee you can’t remember every mile of your last car drive – because you were almost operating on autopilot using a skill you take for granted. Confined space rescue is not a skill you will learn and then apply everyday – hence it will require more deliberate thought. As the old adage says – practise makes perfect.

Published: 20th Jul 2015 in Health and Safety International

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